Several compounds have been known as antibiotics having xanthone in their basic structure and they include: albofungin (=Kanchanomycin, BA-180265*, P-42-1**) as reported in Tetrahedron Letters, 18, 1751 (1972), Antimicrob. Agent & Chemoth., 767 (1962)*, and J. Antibiotics., 26, 65 (1973)**, lysolipin I as reported in Arch. Microbid., 106, 175 (1975) and Helv. Chim. Acta., 60, 178 (1977); antibiotic AM-5344-A.sub.1 as disclosed in Japanese Patent Application (OPI) No. 9690/1983 (this antibiotic was later designated Cervinomycin A.sub.1); and antibiotic AM-5344-A.sub.2 as disclosed in Japanese Patent Application (OPI) No. 102897/1982 (this antibiotic was later designated Cervinomycin A.sub.2) now U.S. Pat. No. 4,666,715.
The present inventors investigated the solubility and toxicity of the cervinomycin compounds mentioned above and found that they were very poorly soluble in a variety of solvents, had strong toxicity and that they exhibited weak activity against Mycoplasmas and certain Gram-positive bacteria.
Under these circumstances, it is necessary for the purposes of medical treatment of human and animal subjects to develop novel derivatives of cervinomycin that have enhanced solubility, improved antibacterial activity and reduced toxicity.